The review made me feel better about buying the 16GB. More storage and faster performance overall. Write speeds have felt quicker compared to my Verizon Galaxy Nexus when transferring x264 tv shows. Long time lurker, first comment. Love the site and keep it up.Reply

Yup, these are just synthetic tests, need some kind of real-world testing even if it's not as complete as the storage benchmarks Anand uses in SSD reviews. If a 30% synthetic improvement only means a <5% real-world improvement it's only of academic interest.Reply

Thanks for bringing these issues to the forefront. I really hope Anandtech will continue to benchmark I/O performance on mobile devices.

I've seen many folks complain about Tegra 3 performance not meeting expectations given that it is a quad core cpu. However, from my own experiments it is fairly obvious that I/O is the bottleneck in most real world cases. The Android browser is much, much faster if you move it along with the it's cache and database to memory or even move it to a fast microSD card.Reply

I'm unaware of any iOS storage benchmark app, but one can get a rough feeling for the sequential write performance by seeing how fast large files (eg movies) copy to a device which is connected via USB. By that metric, iPad1, iPhone4 and iPad3 can all write at around 18..20 MB/s. I haven't tested an iPhone 4S, but given the pattern above I imagine it is the same.

I suspect the random write performance, while perhaps not as bad as we see here, is not much better (perhaps 2x better if we assume very simple scaling?) In my substantial use of iOS devices I'd say this random write performance is still too low. There are few occasions on which my iPhone4 stutters, and they all seem to be related to having to write out a bunch of misc data.

[It is possible that this may be substantially improved in iOS6. A big problem with Lion was that the VM system did not maintain enough clean pages in reserve for large memory requests, so most of the long pauses for VM on Lion were actually pauses to write out dirty pages, not pauses to read in new data. This has been very impressively fixed in Mountain Lion. Obviously iOS uses VM somewhat differently from Lion, and it's not clear to me the exact conditions under which it pages out, but it's certainly possible that it might have suffered from this same problem, and has the same fix as Mountain Lion, which might mean substantially fewer waits for a large bolus of writes to pass through the system on iOS6.]

In terms of real world use cases, I see random write performance as by far the most important immediate issue. Faster sequential write would be nice on those rare occasions when you plug your device into a computer and have to wait while it syncs a large number of movies and songs, but those occasions were rare and, with wireless syncing, are becoming rarer.I'm not sure that anything that actually matters will be improved by better read performance, either sequential or random.

[This is my experience with iOS. I have no experience with Android, and if someone is willing to give a good explanation of why it could benefit from, eg, better random read performance, I think we'd all appreciate that.]Reply

Anand, great info here. One thing I noticed with my N7 is that it would occasionally lock up or lag horribly on touch inputs rendering it almost unusable. I eventually tracked the issue down to push notifications, and figured maybe something was going on with I/O when data was being written from those. I'd filled my tablet up with movies for a long trip, and when I deleted them the issue all but disappeared. I'd be really interested to see benchmarks for both when the storage is almost completely in use (in my case I had ~1GB free) vs empty, which I assume is what you tested here? Just to find out if my hunch that using that storage does affect the device badly is correct.Reply

Others should be advised that there is an issue if you fill up the 16GB model to the point where it only has 3GB left; the speed plummets and the thing is incredibly laggy. I loved mine up to the point where this happened. It seems the people at Google are looking into it but otherwise buyer beware.

I have been testing my 3rd Nexus 7 quite vigorously. My previous 2 tablets performed horrendously when almost full as the links by the previous poster suggest. I had a few build quality issues with them so I returned them for a new one.

Here are my latest results after installing lots of apps and adding lots of movies:

Android 4.1 <- I am refusing the update prompt that persistently nags me since I believe this may be causing the slow issue.